Main.cc: In function 'int main()':
Main.cc:13:13: error: 'a' was not declared in this scope
if(!a[t])s++;
^
Main.cc:17:13: error: 'a' was not declared in this scope
a[t]=1;
^
Main.cc:8:13: warning: unused variable 'i' [-Wunused-variable]
int n,m,i,t=0,s=0,r=0;
^