#include<stdio.h>
int main()
{
    int paymentAmount,accountBalance,isActive;
    if(scanf("%d",&paymentAccount) !=1||
    scanf("%d",&accountBalance) !=1 ||
    scanf("%d",&isActive) !=1){
        printf("Invalid input");
        return 0;
    }
    if(isActive==0)
    {    
         printf("Account is invalid");
        
    }
    else if(paymentAmount > accountBalance)
    {
        printf("Insufficient Balance");
        
    }
    else
    {
        float remainingBalance=accountBalance-paymentAmount;
        printf("%.2f",remainingBalance);
    }
    return 0;
}