#include <algorithm>
#include <array>
#include <bitset>
#include <cassert>
#include <chrono>
#include <climits>
#include <cmath>
#include <complex>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <vector>
#include <stack>
using namespace std;
#define int long long
#define mp make_pair
#define fi first
#define pii pair<int,int>
#define se second
const int INF=1000000000000000000;
const int N=200000;
const int M=998244353;
const int ln=20;
struct Mint{   
    int n;
    Mint(int nn){
        n=nn%M;
    }
    Mint(){
        n=0;
    }
    Mint& operator+=(Mint const& m){
        n=(n+m.n)%M;
        return *this;
    }
    Mint& operator*=(Mint const& m){
        n=(n*m.n)%M;
        return *this;
    }
    Mint& operator-=(Mint const& m){
        n=(n+M-m.n)%M;
        return *this;
    }
    friend Mint binpow(Mint a,int b){
        if(b==0) return Mint(1);
        Mint r=binpow(a,b/2LL);
        r*=r;
        if(b%2==0) return r;
        r*=a;
        return r;
    }
    friend Mint inverse(Mint a){
        return binpow(a,M-2);
    }
    Mint& operator/=(Mint const &b){
        return (*this)*=inverse(b);
    }
    friend Mint operator+(Mint a,Mint const b){
        return (a+=b);
    }
    friend Mint operator-(Mint a,Mint const b){
        return (a-=b);
    }
    friend Mint operator*(Mint a,Mint const b){
        return (a*=b);
    }
    friend Mint operator/(Mint a,Mint const b){
        return (a/=b);
    }
    friend Mint operator-(Mint a){
        return 0-a;
    }
    friend std::ostream& operator<<(std::ostream& os, Mint const& a){
        return os << a.n;
    }
    friend std::istream& operator>>(std::istream& is, Mint& a){
        return (is >> a.n);
    }
    friend bool operator==(Mint const& a,Mint const& b){
        return a.n==b.n;
    }
    friend bool operator!=(Mint const& a,Mint const& b){
        return a.n!=b.n;
    }
};
template<typename T>
std::ostream& operator<< (std::ostream& os,pair<T,T> p){
    return os << p.fi << " " << p.se << "\n";
}
void solve(){
    int n,q;
    cin >> n >> q;
    string ss,tt;
    cin >> ss >> tt;
    int s[n];
    int t[n];
    for(int i=0;i<n;i++) s[i]=(ss[i]-'a');
    for(int i=0;i<n;i++) t[i]=(tt[i]-'a');
    if(true){
        int es=0;
        int os=0;
        int et=0;
        int ot=0;
        for(int i=0;i<n;i++){
            if(i%2==0){
                es+=(s[i]);
                et+=(t[i]);
            }
            if(i%2!=0){
                os+=(s[i]);
                ot+=(t[i]);
            }
        }
        if((et-es)%26==(ot-os)%26){
            cout << "da\n";
        } else{
            cout << "ne\n";
        }
        while(q--){
            int i;
            char c;
            cin >> i >> c;
            i--;
            if(i%2==0){
                es-=(s[i]);
                es+=(c-'a');
            } else{
                os-=(s[i]);
                os+=(c-'a');
            }
            s[i]=(c-'a');
            if((et+os)%26==(ot+es)%26){
                cout << "da\n";
            } else cout << "ne\n"; 
        }
    }
}
signed main(){
    auto begin = std::chrono::high_resolution_clock::now();
    ios_base::sync_with_stdio(false);
    cin.tie(NULL); cout.tie(NULL);
    solve();
    auto end = std::chrono::high_resolution_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::nanoseconds>(end - begin);
    cerr << "Time measured: " << elapsed.count() * 1e-9 << " seconds.\n"; 
}
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