#include <bits/stdc++.h> using namespace std; int main(){ int n,q; cin >> n >> q; string a,b; cin >> a >> b; int d = b[0] - a[0]; for(int i = 1 ; i < n ; i++){ d = b[i] - (a[i]+d); } cout << (d == 1 ? "ne\n" : "da\n"); while(q--){ int idx; char c; cin >> idx >> c; idx--; a[idx] = c; d = b[0] - a[0]; for(int i = 1 ; i < n ; i++){ d = b[i] - (a[i]+d); } cout << (d == 1 ? "ne\n" : "da\n"); } }