foo.c: In function 'main':
foo.c:29:8: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
        if(read[0]==2) s[i]=4;break;
        ^~
foo.c:29:30: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
        if(read[0]==2) s[i]=4;break;
                              ^~~~~
foo.c:32:8: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
        if(read[0]==2) s[i]=5;break;
        ^~
foo.c:32:30: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
        if(read[0]==2) s[i]=5;break;
                              ^~~~~
foo.c:35:8: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
        if(read[0]==2) s[i]=2;break;
        ^~
foo.c:35:30: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
        if(read[0]==2) s[i]=2;break;
                              ^~~~~
foo.c:9:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&N,&M);
  ^~~~~~~~~~~~~~~~~~~
foo.c:15:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&read[i]);
     ^~~~~~~~~~~~~~~~~~~~
foo.c:23:7: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d",&read[i]);
       ^~~~~~~~~~~~~~~~~~~~
foo.c:7:7: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
  int* s;
       ^