Language: C

n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'n' [-Wimplicit-int]
main.c:1:3: error: type defaults to 'int' in declaration of 'g' [-Wimplicit-int]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |   ^
main.c:1:13: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |             ^
main.c:1:15: warning: data definition has no type or storage class
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |               ^
main.c:1:15: error: type defaults to 'int' in declaration of 'x' [-Wimplicit-int]
main.c:1:17: error: type defaults to 'int' in declaration of 'X' [-Wimplicit-int]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                 ^
main.c:1:19: error: return type defaults to 'int' [-Wimplicit-int]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                   ^
main.c: In function 'D':
main.c:1:19: error: type of 'S' defaults to 'int' [-Wimplicit-int]
main.c:1:19: error: type of 'G' defaults to 'int' [-Wimplicit-int]
main.c:1:50: error: implicit declaration of function 'memset' [-Wimplicit-function-declaration]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                  ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'memset'
  +++ |+#include <string.h>
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
main.c:1:50: warning: incompatible implicit declaration of built-in function 'memset' [-Wbuiltin-declaration-mismatch]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                  ^~~~~~
main.c:1:50: note: include '<string.h>' or provide a declaration of 'memset'
main.c:1:108: error: expected expression before '?' token
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                            ^
main.c: At top level:
main.c:1:174: error: return type defaults to 'int' [-Wimplicit-int]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                              ^~~~
main.c: In function 'main':
main.c:1:174: error: type of 'y' defaults to 'int' [-Wimplicit-int]
main.c:1:174: error: type of 'Y' defaults to 'int' [-Wimplicit-int]
main.c:1:188: warning: incompatible implicit declaration of built-in function 'memset' [-Wbuiltin-declaration-mismatch]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                                            ^~~~~~
main.c:1:188: note: include '<string.h>' or provide a declaration of 'memset'
main.c:1:197: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                                                     ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
main.c:1:197: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                                                     ^~~~~
main.c:1:197: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:287: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                                                                                                                                               ^~~~
main.c:1:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
  +++ |+#include <stdlib.h>
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
main.c:1:287: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
    1 | n,g[21][21],i;x,X;D(S,G){int c[21],f[21]={0};for(memset(c,1,84),c[S]=0;S;){for(i=n+1;--i;c[i]=c[S]+g[S][i]<?c[i])f[S]=1;for(S=i=0;++i<=n;)S=f[i]|c[i]>c[S]?S:i;}return c[G];}main(y,Y){for(memset(g,scanf("%d%d",&n,&i),1764);~i--;~i&&(g[x][X]=y,g[X][x]=Y))scanf("%d,%d,%d,%d",&x,&X,&y,&Y);exit(!printf("%d\n",y-Y-D(x,X)-D(X,x)));}
      |                                                                                                                                                                                                                                                                                               ^~~~
main.c:1:287: note: include '<stdlib.h>'