Gaussian operation, I don't know what the problem is talking about...
It turns out that it refers to the fact that rows cannot be exchanged
//
// GGGGGGGGGGGGG CCCCCCCCCCCCC AAA
// GGG::::::::::::G CCC::::::::::::C A:::A
// GG:::::::::::::::G CC:::::::::::::::C A:::::A
// G:::::GGGGGGGG::::G C:::::CCCCCCCC::::C A:::::::A
// G:::::G GGGGGG C:::::C CCCCCC A:::::::::A
//G:::::G C:::::C A:::::A:::::A
//G:::::G C:::::C A:::::A A:::::A
//G:::::G GGGGGGGGGGC:::::C A:::::A A:::::A
//G:::::G G::::::::GC:::::C A:::::A A:::::A
//G:::::G GGGGG::::GC:::::C A:::::AAAAAAAAA:::::A
//G:::::G G::::GC:::::C A:::::::::::::::::::::A
// G:::::G G::::G C:::::C CCCCCC A:::::AAAAAAAAAAAAA:::::A
// G:::::GGGGGGGG::::G C:::::CCCCCCCC::::C A:::::A A:::::A
// GG:::::::::::::::G CC:::::::::::::::C A:::::A A:::::A
// GGG::::::GGG:::G CCC::::::::::::C A:::::A A:::::A
// GGGGGG GGGG CCCCCCCCCCCCCAAAAAAA AAAAAAA
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
#include <ctime>
using namespace std;
#ifdef DEBUG
#define VAR(a,b) decltype(b) a=(b)
#define debug(...) printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)
#define gettime() end\_time=clock();printf("now running time is %.7f\\n",(float)(end\_time - start\_time)/CLOCKS\_PER\_SEC);
#else
#define VAR(a,b) \_\_typeof(b) a=(b)
#define debug(...)
#define gettime()
#endif
typedef unsigned int uint;
typedef long long int Int;
typedef unsigned long long int UInt;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\\n")
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()
#define De(x)printf(#x"%d\\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\
printf("%d ",dp\[htx\]\[hty\]);}Pln();}
#define M 1005
#define PII pair<int,int\>
#define PB push\_back
#define oo INT\_MAX
#define Set\_oo 0x3f
#define FOR(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define eps 1e-6
#define X first
#define Y second
clock\_t start\_time=clock(), end\_time;
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
bool xeqy(double x,double y){return fabs(x-y)<eps;}
int xexy(double x,double y){
if(x>y+eps)return 2;
else if(x>y-eps)return 1;
else if(x<y-eps)return -2;
else if(x<y+eps)return -1;
else if(fabs(x-y)<eps)return 0;
return 3;
}
int min3(int x,int y,int z){
int tmp=min(x,y);
return min(tmp,z);
}
int max3(int x,int y,int z){
int tmp=max(x,y);
return max(tmp,z);
}
int n,m;
double mz\[M\]\[M\];
int main() {
ios\_base::sync\_with\_stdio(0);
while(~scanf("%d",&n)&&n){
m=n+n;
for(int i=0;i<n;i++){
for(int j=0;j<n;j++){
scanf("%lf",&mz\[j\]\[i\]);
}
for(int j=n;j<m;j++){
mz\[j\]\[i\]=0;
}
mz\[i+n\]\[i\]=1;
}
bool suc=true;
for(int i=0;i<n;i++){
// for(int j=0;j<n;j++){
// for(int k=0;k<m;k++)printf("%.2f ",mz\[k\]\[j\]);
// Pln();
// }Pln();
if(xeqy(mz\[i\]\[i\],0)){
suc=false;
break;
}
double t=mz\[i\]\[i\];
for(int j=i;j<m;j++){
mz\[j\]\[i\]/=t;
}
for(int j=0;j<n;j++){
if(xexy(mz\[i\]\[j\],0)==0||i==j)continue;
double t=mz\[i\]\[j\];
for(int k=i;k<m;k++){
mz\[k\]\[j\]-=t\*mz\[k\]\[i\];
}
}
}
if(!suc)puts("Not possible");
else
for(int i=0;i<n;i++){
printf("%.6f",mz\[n\]\[i\]);
for(int j=n+1;j<m;j++){
printf(" %.6f",mz\[j\]\[i\]);
}Pln();
}
Pln();
}
}