#include <iostream>
#include <string>
#include <vector>

using namespace std;

int main() {
    size_t len;
    string s1, s2;
    std::cin >> len >> s1 >> s2;

    size_t pref = 0, suff = len - 1;
    while (s1[pref] == s2[pref]) {
        ++pref;
    }
    while (s1[suff] == s2[suff]) {
        --suff;
    }

    string t11 = s1.substr(0, pref) + s2[pref] + s1.substr(pref, len - pref);
    string t12 = s2.substr(0, suff + 1) + s1[suff] + s2.substr(suff + 1, len - suff);

    string t21 = s2.substr(0, pref) + s1[pref] + s2.substr(pref, len - pref);
    string t22 = s1.substr(0, suff + 1) + s2[suff] + s1.substr(suff + 1, len - suff);

    if (t11 == t12 && t21 == t22) {
        if (t11 == t21) {
            cout << "1\n";
        } else {
            cout << "2\n";
        }
    } else if (t11 == t12 || t21 == t22) {
        cout << "1\n";
    } else {
        cout << "0\n";
    }

    return 0;
}