#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> VI;
typedef vector<VI> VVI;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
const int MOD = int(1e9+7);

int N,M,W,H;
int res = 0;

unsigned int xor128(void) {
    static unsigned int x=123456789,y=362436069,z=521288629,w=88675123;
    unsigned int t=(x^(x<<11));x=y;y=z;z=w; return( w=(w^(w>>19))^(t^(t>>8)) );
}

int A[11],B[11];

int main(){
    cin >> N;
    REP(i,N) cin >> A[i];
    REP(i,N) cin >> B[i];

    clock_t t = clock() + CLOCKS_PER_SEC * 4;
    int total = 0, win = 0;
    while(t >= clock()){
        int aw = 0, bw = 0;
        for(int i = 0; i < N; i++){
            int ai = xor128()%(N-i)+i;
            int bi = xor128()%(N-i)+i;

            swap(A[i],A[ai]);
            swap(B[i],B[bi]);

            if(A[i]>B[i]) aw++; else bw++;
        }
        if(aw > bw) win++;
        total++;
    }


    cout << setprecision(9) << (1.*win/total) << endl;
    return 0;
}