#include using namespace std; using ll=long long; using pp=pair; #define sr string #define vc vector #define db double #define fi first #define se second #define rep(i,n) for(int i=0;i<(int)n;i++) #define pb push_back #define all(v) v.begin(),v.end() #define pque priority_queue #define bpc(a) __builtin_popcount(a) int main(){ int n; sr s;cin>>n>>s; n*=3; vc v(3,vc(3,0)); sr con="con"; rep(i,n)rep(j,3)if(s[i]==con[j])v[i%3][j]++; int ans=0; rep(i,3){ int mn=n; rep(j,3)mn=min(mn,v[i][j]); ans+=mn; } cout<