@[LIUYIFAN5](/user/1055807)
```cpp
#include<bits/stdc++.h>
using namespace std;
long long a[60000005],n,j=1;
long long mod(long long i){
if(a[i])return a[i];//记忆化
if(i==1||i==2)return a[i]=1%n;
else return a[i]=(mod(i-1)+mod(i-2))%n;//else可以不要
}
int main(){
cin>>n;
while(mod(j)!=0||mod(j+1)!=1)j++;
cout<<j;
return 0;
}
```
by oymz @ 2023-11-12 16:52:20