怎么不输出？

#include<bits/stdc++.h>
using namespace std;
int main(){
    int a;
    string b;
    char c,d;
    string e;
    cin>>a>>b>>c>>d>>e;
    if(b=="GB"){
        if(e=="GB"){
            cout<<fixed<<setprecision(6)<<a*1<<endl;
            return 0;
        }
        else
         if(e=="MB"){
            cout<<fixed<<setprecision(6)<<a*1024<<endl;
            return 0;
        }
        else
         if(e=="KB"){
            cout<<fixed<<setprecision(6)<<a*1024*1024<<endl;
            return 0;
        }
        else
         if(e=="B"){
            cout<<fixed<<setprecision(6)<<a*1024*1024*1024<<endl;
            return 0;
        }
    }
    else
     if(b=="MB"){
        if(e=="GB"){
            cout<<fixed<<setprecision(6)<<(a/1024)<<endl;
            return 0;
        }
        else
         if(e=="MB"){
            cout<<fixed<<setprecision(6)<<a<<endl;
            return 0;
        }
        else
         if(e=="KB"){
            cout<<fixed<<setprecision(6)<<a*1024<<endl;
            return 0;
        }
        else
         if(e=="B"){
            cout<<fixed<<setprecision(6)<<a*1024*1024<<endl;
            return 0;
        }
    }
    else
    if(b=="KB"){
        if(e=="GB"){
            cout<<fixed<<setprecision(6)<<a/1024/1024<<endl;
            return 0;
        }
        else
         if(e=="MB"){
            cout<<fixed<<setprecision(6)<<a/1024<<endl;
            return 0;
        }
        else
         if(e=="KB"){
            cout<<fixed<<setprecision(6)<<a<<endl;
            return 0;
        }
        else
         if(e=="B"){
            cout<<fixed<<setprecision(6)<<a*1024<<endl;
            return 0;
        }
    }
    else
    if(b=="B"){
        if(e=="GB"){
            cout<<fixed<<setprecision(6)<<a/1024/1024/1024<<endl;
            return 0;
        }
        else
         if(e=="MB"){
            cout<<fixed<<setprecision(6)<<a/1024/1024<<endl;
            return 0;
        }
        else
         if(e=="KB"){
            cout<<fixed<<setprecision(6)<<a/1024<<endl;
            return 0;
        }
        else
         if(e=="B"){
            cout<<fixed<<setprecision(6)<<a<<endl;
            return 0;
        }
    }
    return 0;
}