Language: C

a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}

Compiler output:
main.c:1:1: warning: data definition has no type or storage class
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      | ^
main.c:1:1: error: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
main.c:1:13: error: variably modified 's' at file scope
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |             ^
main.c:1:18: error: variably modified 't' at file scope
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                  ^
main.c:1:23: warning: data definition has no type or storage class
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                       ^
main.c:1:23: error: type defaults to 'int' in declaration of 'u' [-Wimplicit-int]
main.c:1:23: error: variably modified 'u' at file scope
main.c:1:28: error: type defaults to 'int' in declaration of 'm' [-Wimplicit-int]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                            ^
main.c:1:30: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                              ^
main.c:1:32: error: type defaults to 'int' in declaration of 'j' [-Wimplicit-int]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                ^
main.c:1:34: error: type defaults to 'int' in declaration of 'c' [-Wimplicit-int]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                  ^
main.c:1:36: error: return type defaults to 'int' [-Wimplicit-int]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                    ^~~~
main.c: In function 'main':
main.c:1:36: error: type of 'n' defaults to 'int' [-Wimplicit-int]
main.c:1:50: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                                  ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
main.c:1:50: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                                  ^~~~~
main.c:1:50: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:75: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                                                           ^~~~~~
main.c:1:75: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:75: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
main.c:1:75: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:99: error: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                                                                                   ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'strlen'
  +++ |+#include <string.h>
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
main.c:1:99: warning: incompatible implicit declaration of built-in function 'strlen' [-Wbuiltin-declaration-mismatch]
    1 | a=4005;char s[a],t[a];u[a],m,i,j,c;main(n){for(;~scanf("%s%s",s,t+1);i=m=!printf("%d\n",m)){for(n=strlen(s);!i|t[i];i++)for(j=n;j--;m<c?m=c:0)u[j+1]=c=s[j]-t[i]?0:u[j]+1;}}
      |                                                                                                   ^~~~~~
main.c:1:99: note: include '<string.h>' or provide a declaration of 'strlen'