#include<stdio.h>
int main(){
    double paymentAmount,accountBalance;
    int isActive;
    if(scanf("%lf",&paymentAmount)!=1||
    scanf("%lf",&accountBalance)!=1||
    scanf("%lf",&isActive)!=1){`
        printf("Invalid input.\n");
        return 0;
    }
    if(paymentAmount<0||paymentAmount>1000000){
        printf("Invalid input.\n");
        return 0;
    }
    if(isActive==0){
        printf("Account inactive.\n");
        return 0;
        
    }
     if(paymentAmount>accountBalance){
        printf("Insufficient Balance.\n");
        return 0;
    }
        double remaining = accountBalance-paymentAmount;
        printf("%.2f\n",remaining);
    
    return 0;
}