#pragma GCC optimize("O3")
#pragma GCC optimize(2)
#pragma GCC optimize(3)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")	
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping") 
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-funroll-loops")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,fma") 
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native") 
//#pragma GCC optimization ("unroll-loops")

#include <bits/stdc++.h>
 
using namespace std;

int dp[2][21][21][21][21];
string s;

// KUROI

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);

    cin >> s;

    memset(dp,-1,sizeof(dp));

    int n = s.length();

    int m = n/5;
    dp[1][0][0][0][0] = 0;

    for(int i=0;i<n;i++)
    {
        for(int a=0;a<=m;a++)
        {
            for(int b=0;b<=m;b++)
            {
                for(int c=0;c<=m;c++)
                {
                    for(int d=0;d<=m;d++)
                    {
                        dp[0][a][b][c][d] = dp[1][a][b][c][d];
                        dp[1][a][b][c][d] = -1;
                    }
                }
            }
        }

        for(int a=0;a<=m;a++)
        {
            for(int b=0;b<=m;b++)
            {
                for(int c=0;c<=m;c++)
                {
                    for(int d=0;d<=m;d++)
                    {
                        if(dp[0][a][b][c][d]==-1) continue;
                        if(s[i]=='K')
                        {
                            if(a+1 <= m)
                            {
                                dp[1][a+1][b][c][d] = max(dp[1][a+1][b][c][d],dp[0][a][b][c][d]);
                            }
                            else
                            {
                                dp[1][m][b][c][d] = max(dp[1][m][b][c][d],dp[0][a][b][c][d]);
                            }
                        }
                        else if(s[i]=='U')
                        {
                            if(a-1>=0)
                            {
                                if(b+1<=m)
                                {
                                    dp[1][a-1][b+1][c][d] = max(dp[1][a-1][b+1][c][d],dp[0][a][b][c][d]);
                                }
                                else
                                {
                                    dp[1][a-1][m][c][d] = max(dp[1][a-1][m][c][d],dp[0][a][b][c][d]);
                                }
                            }
                        }
                        else if(s[i]=='R')
                        {
                            if(b-1>=0)
                            {
                                if(c+1<=m) dp[1][a][b-1][c+1][d] = max(dp[1][a][b-1][c+1][d],dp[0][a][b][c][d]);
                                else dp[1][a][b-1][m][d] = max(dp[1][a][b-1][m][d],dp[0][a][b][c][d]);
                            }
                        }
                        else if(s[i]=='O')
                        {
                            if(c-1>=0)
                            {
                                if(d+1<=m) dp[1][a][b][c-1][d+1] = max(dp[1][a][b][c-1][d+1],dp[0][a][b][c][d]);
                                else dp[1][a][b][c-1][m] = max(dp[1][a][b][c-1][m],dp[0][a][b][c][d]);
                            }                           
                        }
                        else if(s[i]=='I')
                        {
                            if(d-1>=0)
                            {
                                dp[1][a][b][c][d-1] = max(dp[1][a][b][c][d-1],dp[0][a][b][c][d] + 1);
                            }
                        }
                        else if(s[i]=='?')
                        {
                            if(a+1 <= m)
                            {
                                dp[1][a+1][b][c][d] = max(dp[1][a+1][b][c][d],dp[0][a][b][c][d]);
                            }
                            else
                            {
                                dp[1][m][b][c][d] = max(dp[1][m][b][c][d],dp[0][a][b][c][d]);
                            }                          
                            if(a-1>=0)
                            {
                                if(b+1<=m)
                                {
                                    dp[1][a-1][b+1][c][d] = max(dp[1][a-1][b+1][c][d],dp[0][a][b][c][d]);
                                }
                                else
                                {
                                    dp[1][a-1][m][c][d] = max(dp[1][a-1][m][c][d],dp[0][a][b][c][d]);
                                }
                            }
                            if(b-1>=0)
                            {
                                if(c+1<=m) dp[1][a][b-1][c+1][d] = max(dp[1][a][b-1][c+1][d],dp[0][a][b][c][d]);
                                else dp[1][a][b-1][m][d] = max(dp[1][a][b-1][m][d],dp[0][a][b][c][d]);
                            }
                            if(c-1>=0)
                            {
                                if(d+1<=m) dp[1][a][b][c-1][d+1] = max(dp[1][a][b][c-1][d+1],dp[0][a][b][c][d]);
                                else dp[1][a][b][c-1][m] = max(dp[1][a][b][c-1][m],dp[0][a][b][c][d]);
                            }          
                            if(d-1>=0)
                            {
                                dp[1][a][b][c][d-1] = max(dp[1][a][b][c][d-1],dp[0][a][b][c][d] + 1);
                            }                                                
                        }
                        else
                        {
                            dp[1][a][b][c][d] = max(dp[1][a][b][c][d],dp[0][a][b][c][d]);
                        }
                    }
                }
            }
        }      
    }

    int res = 0;

    for(int a=0;a<=m;a++)
    {
        for(int b=0;b<=m;b++)
        {
            for(int c=0;c<=m;c++)
            {
                for(int d=0;d<=m;d++)
                {
                    res = max(res,dp[1][a][b][c][d]);
                }
            }
        }
    }

    cout << res << '\n';

	return 0;
}