Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int t,i,j,k,l,m,n;
    char s[1000];
    cin>>s;
    l=strlen(s);
    for(i=0;i<l;i++)
    {
        if(s[i]=='k')
        {
            if(s[i+1]=='e')
            {
                if(s[i+2]=='y')
                {
                    if(s[i+3]=='e')
                    {
                        if(s[i+4]=='n')
                        {
                            if(s[i+5]=='c')
                            {
                                if(s[i+6]=='e')
                                {
                                    cout<<"YES";
                                    return 0;
                                }
                                for(j=i+6;j<;j++)
                                {
                                    if(s[j]=='e')
                                    {
                                        cout<<"YES";
                                        return 0;
                                    }
                                }
                                cout<<"NO";
                                return 0;
                            }
                            for(j=i+5;j<l;j++)
                            {
                                if(s[j]=='c' && s[j+1]=='e')
                                {
                                    cout<<"YES";
                                    return 0;
                                }
                            }
                            cout<<"NO";
                            return 0;
                        }
                        for(j=i+4;j<l;j++)
                        {
                            if(s[j]=='n' && s[j+1]=='c' && s[j+2]=='e')
                            {
                                cout<<"YES";
                                return 0;
                            }
                        }
                        cout<<"NO";
                        return 0;
                    }
                    for(j=i+3;j<l;j++)
                    {
                        if(s[j]=='e' && s[j+1]=='n' && s[j+2]=='c' && s[j+3]=='e')
                        {
                            cout<<"YES";
                            return 0;
                        }
                    }
                    cout<<"NO";
                    return 0;
                }
                for(j=i+2;j<l;j++)
                {
                    if(s[j]=='y' && s[j+1]=='e' && s[j+2]=='n' && s[j+3]=='c' && s[j+4]=='e')
                    {
                        cout<<"YES";
                        return 0;
                    }
                }
                cout<<"NO";
                return 0;
            }
            for(j=i+1;j<l;j++)
            {
                if(s[j]=='e' && s[j+1]=='y' && s[j+2]=='e' && s[j+3]=='n' && s[j+4]=='c' && s[j+5]=='e')
                {
                    cout<<"YES";
                    return 0;
                }
            }
            cout<<"NO";
            return 0;
        }
    }
    cout<<"NO";
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:28:45: error: expected primary-expression before ';' token
   28 |                                 for(j=i+6;j<;j++)
      |                                             ^