#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define pb push_back
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define vtpl(x,y,z) vector<tuple<x,y,z>>
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={0,1,-1,0,1,1,-1,-1,0};
const ll dx[9]={1,0,0,-1,1,-1,1,-1,0};
template<class T> inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
} 
string t="KUROI?";
int main(){
    string s;cin >> s;
    string ns;
    rep(i,s.size()){
        rep(j,6)if(s[i]==t[j])ns+=s[i];
    }
    s=ns;
    ll dp[21][21][21][21];
    memset(dp,-inf,sizeof(dp));dp[0][0][0][0]=0;
    rep(i,s.size()){
        ll ndp[21][21][21][21];
        memset(ndp,-inf,sizeof(ndp));
        rep(a,21)rep(b,21)rep(c,21)rep(d,21){
            chmax(ndp[a][b][c][d],dp[a][b][c][d]);
            if(s[i]=='K'||s[i]=='?'){
                if(a+1<=20)chmax(ndp[a+1][b][c][d],dp[a][b][c][d]);
            }
            if(s[i]=='U'||s[i]=='?'){
                if(b+1<=20&&a>=1)chmax(ndp[a-1][b+1][c][d],dp[a][b][c][d]);
            }
            if(s[i]=='R'||s[i]=='?'){
                if(c+1<=20&&b>=1)chmax(ndp[a][b-1][c+1][d],dp[a][b][c][d]);
            }
            if(s[i]=='O'||s[i]=='?'){
                if(d+1<=20&&c>=1)chmax(ndp[a][b][c-1][d+1],dp[a][b][c][d]);
            }
            if(s[i]=='I'||s[i]=='?'){
                if(d>=1)chmax(ndp[a][b][c][d-1],dp[a][b][c][d]+1);
            }
        }
        swap(dp,ndp);
    }
    ll ans=0;
    rep(a,21)rep(b,21)rep(c,21)rep(d,21)chmax(ans,dp[a][b][c][d]);
    cout << ans << endl;
}