#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define int long long
#define pii pair<int,int>
#define vi vector<int>
#define ff first
#define ss second
#define sp << " " <<
#define all(x) x.begin(),x.end()
#define big(x) ((int)(x.size()))
using namespace std;
const int MOD = 1e9+7, LIM = 1e6+1, inf = 2e9;
const int N = 1e5+1;
void solve() {
    int n,q;
    cin >> n >> q;
    string s,t;
    cin >> s >> t;
    int sm1 = 0,sm2 = 0;
    for (int i = 0;i<n;i+=2) sm1+=s[i];
    for (int i = 1;i<n;i+=2) sm1-=s[i]; 
    sm1+=20000000000*26;
    for (int i = 0;i<n;i+=2) sm2+=t[i];
    for (int i = 1;i<n;i+=2) sm2-=t[i]; 
    sm2+=20000000000*26;
    cout << ((sm1%26 == sm2%26)?"da\n":"ne\n");
    while (q--) {
        int p;
        char c;
        cin >> p >> c;
        if ((p-1)%2 == 0) sm1-=s[p-1];
        else sm1+=s[p-1];
        s[p-1] = c;
        if ((p-1)%2 == 0) sm1+=s[p-1];
        else sm1-=s[p-1];
        cout << ((sm1%26 == sm2%26)?"da\n":"ne\n");
    }
} 
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    #ifdef Dodi
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    #endif
    int t = 1;
    //cin >> t;
    while (t --> 0) solve();
}
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