#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <list>
#include <stdio.h>

using namespace std;
int*pv,*nt;
int dp1[21][21][21][21];
int dp2[21][21][21][21];
const int INF = 1e6;
#define id(a,b,c,d) (a)*21*21*21+(b)*21*21+(c)*21+(d)
int main() {
    string str;
    cin>>str;
    int n=str.size();
    pv=(int*)dp1;
    nt=(int*)dp2;

    for(int i = 0; i < 21; i++)
        for(int j = 0; j < 21; j++)
            for(int k = 0; k < 21; k++)
                for(int l = 0; l < 21; l++)
                    pv[id(i,j,k,l)]=-INF;
    pv[id(0,0,0,0)]=0;

    int res=0;
    for(int m = 0; m < n; m++){
        for(int i = 0; i <21 ; i++)
            for(int j = 0; j < 21; j++)
                for(int k = 0; k < 21; k++)
                    for(int l = 0; l < 21; l++){
                        nt[id(i,j,k,l)]=pv[id(i,j,k,l)];
                        if(str[m]=='K'||str[m]=='?')
                            nt[id(i,j,k,l)]=max((i>0)?pv[id(i-1,j,k,l)]:-INF,nt[id(i,j,k,l)]);
                        if(str[m]=='U'||str[m]=='?')
                            nt[id(i,j,k,l)]=max((j>0&&i<20)?pv[id(i+1,j-1,k,l)]:-INF,nt[id(i,j,k,l)]);
                        if(str[m]=='R'||str[m]=='?')
                            nt[id(i,j,k,l)]=max((k>0&&j<20)?pv[id(i,j+1,k-1,l)]:-INF,nt[id(i,j,k,l)]);
                        if(str[m]=='O'||str[m]=='?')
                            nt[id(i,j,k,l)]=max((l>0&&k<20)?pv[id(i,j,k+1,l-1)]:-INF,nt[id(i,j,k,l)]);
                        if(str[m]=='I'||str[m]=='?')
                            nt[id(i,j,k,l)]=max((l<20)?(pv[id(i,j,k,l+1)]+1):-INF,nt[id(i,j,k,l)]);
                        res=max(res,nt[id(i,j,k,l)]);
                    //   printf("%d:dp[%d][%d][%d][%d]=%d\n",m,i,j,k,l,nt[id(i,j,k,l)]);
                        }
        swap(pv,nt);
    }
    cout<<res<<endl;

    return 0;
}