题解 | 不要三句号的歪

#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    cin>>s;
    long long tail=s.find_last_of(',');
    string stringtail=s.substr(tail+1);
    long long  numtail=stoll(stringtail,nullptr,10);
    long long first=s.find(',');
    long long i=first+1;
    string stringfirst="";
    while(isdigit(s[i]))
    {
        stringfirst+=s[i];
        i++;
        
    }
    long long numfirst=stoll(stringfirst,nullptr,10);
    cout<<numtail-numfirst-1;


}