#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
string addition(const string& num1, const string& num2) {
    string result;
    int carry = 0;
    int i = num1.size() - 1;
    int j = num2.size() - 1;
    while (i >= 0 || j >= 0 || carry > 0) {
        int sum = carry;
        if (i >= 0) sum += num1[i--] - '0';
        if (j >= 0) sum += num2[j--] - '0';
        carry = sum / 10;
        result.push_back(sum % 10 + '0');
    }
    reverse(result.begin(), result.end());
    return result;
}
void A_B_Problem(){
    string num1, num2;
    cin >> num1 >> num2;
    cout << addition(num1, num2) << endl;
}
int main() {
    A_B_Problem();
    return 0;
}

太多题解了,看不出来. . . . . .