#include<stdio.h>
typedef struct cart
{
    char name[20];
    int id;
    float price;
}crt;
int main()
{
    int n;
    scanf("%d",&n);
    if(n<=0){
        printf("Invalid input");
        return 0;
    }
    crt arr[n];
    float sum=0;
    for(int i=0;i<n;i++)
    {
        scanf("%s %d %f",arr[i],name,&arr[i].id,&arr[i].price);
        int j;
        for(j=0;arr[i].name[j]!='\0';j++)
        {
            if(!isalnum(arr[i].name[j]))
            {
                 printf("Invalid input");
                 return 0;
            }
        }
        sum==arr[i].price;
    }
    printf("%.2f",sum);
}