cf 5a Chat Server's Outgoing Traffic

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
using namespace std;
char s[105];
int num,ans;
int main()
{
    num=0;ans=0;
    while(gets(s))
    {
        if(s[0]=='+')
            num++;
        else if(s[0]=='-')
            num--;
        else
        {
            int pos=1;
            while(s[pos]!=':')
                pos++;
            ans+=(strlen(s)-pos-1)*num;
        }
        //printf("ans=%d\n",ans);
    }
    printf("%d\n",ans);
}