#include <cstdio>
int calculator ( const int& a, const int& b, const char& s ) {
switch ( s ) {
case '+' :
return a + b;
case '-' :
return a - b;
case '*' :
return a * b;
case '/' :
if ( b == 0 ) {
puts( "error" ); return 0;
}
return a / b;
case '%' :
return a % b;
default :
puts( "error" );
return 0;
}
}
int main() {
int val_1 = 0;
int val_2 = 0;
char oprt = NULL;
puts( "equation? " );
scanf( "%d %c %d", &val_1, &oprt, &val_2 );
printf( "ans: %d\n", calculator( val_1, val_2, oprt ) );
}