#include <bits/stdc++.h> using namespace std; int main(){ ios::sync_with_stdio(0);cin.tie(0); 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++){ int D = b[i] - (a[i]+d); d = D; } cout << (d == 0 ? "da\n" : "ne\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 == 0 ? "da\n" : "ne\n"); } }