#include <iostream> using namespace std; int a[10000], b[10000]; int main() { string s1, s2; cin >> s1 >> s2; if (s1.size()<s2.size()|| (s1.size()==s2.size()&&s1<s2)){ cout <<'-'; swap(s1,s2);} for (int i = 0; i <= s1.size(); i++) a[s1.size() - 1 - i] = s1[i] - '0'; for (int i = 0; i <= s2.size(); i++) b[s2.size() - 1 - i] = s2[i] - '0'; for (int i = 0; i < max(s1.size(), s2.size()); i++) { a[i] -= b[i]; if (a[i] <0) { a[i] += 10; a[i + 1] --; } } int len = max(s1.size(), s2.size()); while(len>1&&a[len-1]==0)len--; for (int i = len - 1; i >= 0; i--) cout << a[i]; return 0; }