why my soln is incorrect? can anyone help!!
class Solution {\npublic:\n    #define ll long long int\n    const ll p= 1e9+7;\n    ll power(ll x, ll y)\n    {\n        ll res = 1; \n\n        x = x % p; \n\
class Solution {\npublic:\n    #define ll long long int\n    const ll p= 1e9+7;\n    ll power(ll x, ll y)\n    {\n        ll res = 1; \n\n        x = x % p; \n\n        while (y > 0) \n        {\n            if (y & 1)\n                res = (res * x) % p;\n\n\n            y = y >> 1; \n            x = (x * x) % p;\n        }\n        return res;\n    }\n    ll modInverse(ll n)\n    {\n        return power(n, p - 2);\n    }\n    ll ncr(ll n,ll r)\n    {\n\n        if (n < r)\n            return 0;\n\n        if (r == 0)\n            return 1;\n\n\n        ll fac[n + 1];\n        fac[0] = 1;\n        for (int i = 1; i <= n; i++)\n            fac[i] = (fac[i - 1] * i) % p;\n\n        return (fac[n] * modInverse(fac[r]) % p\n                * modInverse(fac[n - r]) % p)\n               % p;\n    }\n    int stringCount(int n) {\n        if(n<4)\n            return 0;\n        ll ans=(ncr(n,4)* 12)%p;\n        ans= (ans%p * power(26,n-4)%p)%p;\n        return ans%p;\n    }\n};
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