题解

#include <iostream>
using namespace std;
int main(){
int a;
cin >> a;
if (a<=17){
printf("%.1lf",a3.4);
}else if (a<=30){
printf("%.1lf",173.4+(a-17)5.32);
}else{
printf("%.1lf",173.4+13*5.32+(a-30)*7);
}
return 0;
}