app.c:6:6: warning: return type of 'main' is not 'int' [-Wmain]
void main()
^
app.c: In function 'main':
app.c:10:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d%d", &N, &M);
^
app.c:11:21: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
for (i = 0; i<N; scanf("%d", m + i++));
^
app.c:12:21: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
for (i = 0; i<N; scanf("%d", c + i++));
^