View Compilation Error

0_0_27684983_12178.cpp: In function 'int main()':
0_0_27684983_12178.cpp:4:2: error: '_int64' was not declared in this scope
  _int64 n,m;
  ^
0_0_27684983_12178.cpp:5:28: error: 'n' was not declared in this scope
  while(scanf("%I64d%I64d",&n,&m)!=EOF)
                            ^
0_0_27684983_12178.cpp:5:31: error: 'm' was not declared in this scope
  while(scanf("%I64d%I64d",&n,&m)!=EOF)
                               ^