#include<iostream>
#include<string>

using namespace std;

string calculate(string num1, string num2, char opr, int base);

int main(){
    string num1,num2;
    char opr;
    int base;
    cin>>num1>>num2>>opr>>base;
    cout<<endl<<calculate(num1,num2,opr,base);
}

string calculate(string num1, string num2, char opr, int base){
    int n1=stoi(num1),n2=stoi(num2),r1=0,r2=0;
    char newbase[16] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};

    for(int i=0;i<(num1.length());i++){
        r1=r1+(n1%10);
        n1/=10;
    }
    for(int i=0;i<(num2.length());i++){
        r2=r2+(n2%10);
        n2/=10;
    }

    string result;
    switch(opr){
    case '+':
        result = r1+r2;
        break;
    case'-':
        result=r1-r2;
        break;
    case'*':
        result=r1*r2;
        break;
    }
    int temp = 0;
    int r=stoi(result);

    string out = "";

    while (r > 0)
    {
        temp = r % base;
        out = newbase[temp] + out;
        r = r / base;
    }
    return to_string(temp);

}