#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
//#define int long long
#define ll long long
typedef unsigned long long ull;
using namespace std;
const int N=1e6+5;
int n,q,a[N];
char s[N],z[N];
int32_t main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
cin>>n>>q;
for (int i=1;i<=n;i++) cin>>s[i];
for (int i=1;i<=n;i++) cin>>z[i];
for (int i=1;i<=n;i++) a[i]=((z[i]-'a')-(s[i]-'a')+26)%26;
for (int Q=0;Q<=q;Q++){
if (Q){
int i;char c;
cin>>i>>c;
s[i]=c;
a[i]=((z[i]-'a')-(s[i]-'a')+26)%26;
}
//for (int i=1;i<=n;i++) cout<<a[i]<<' ';cout<<endl;
int p=0;
for (int i=1;i<n;i++) p=26-a[i]-p;
p+=26*10000000;
p%=26;
if ((a[n]+p)%26) cout<<"ne"<<endl;
else cout<<"da"<<endl;
}
return 0;
}
