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


#define li          long long int
#define rep(i,to)   for(li i=0;i<((li)(to));i++)
#define repp(i,start,to)    for(li i=(li)(start);i<((li)(to));i++)
#define pb          push_back
#define sz(v)       ((li)(v).size())
#define bgn(v)      ((v).begin())
#define eend(v)     ((v).end())
#define allof(v)    (v).begin(), (v).end()
#define dodp(v,n)       memset(v,(li)n,sizeof(v))
#define bit(n)      (1ll<<(li)(n))
#define mp(a,b)     make_pair(a,b)
#define rin rep(i,n)
#define EPS 1e-12
#define ETOL 1e-8
#define MOD 1000000007
typedef pair<li, li> PI;

#define INF bit(60)

#define DBGP 1


#define idp if(DBGP)
#define F first
#define S second
#define p2(a,b)     idp cout<<a<<"\t"<<b<<endl
#define p3(a,b,c)       idp cout<<a<<"\t"<<b<<"\t"<<c<<endl
#define p4(a,b,c,d)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<endl
#define p5(a,b,c,d,e)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<endl
#define p6(a,b,c,d,e,f)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<endl
#define p7(a,b,c,d,e,f,g)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<endl
#define p8(a,b,c,d,e,f,g,h)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<endl
#define p9(a,b,c,d,e,f,g,h,i)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<endl
#define p10(a,b,c,d,e,f,g,h,i,j)        idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<"\t"<<j<<endl
#define foreach(it,v)   for(__typeof((v).begin()) it=(v).begin(); it!=(v).end(); ++it)
#define p2p(x)      idp p2((x).F, (x).S)
#define dump(x,n)   idp{rep(i,n){cout<<x[i]<<" ";}puts("");}
#define dump2(x,n)  idp{rep(i,n){cout<<"["<<x[i].F<<" , "<<x[i].S<<"] ";}puts("");}
#define dumpi(x)    idp{foreach(it, x){cout<<(*it)<<" ";}puts("");}
#define dumpi2(x)   idp{foreach(it, x){cout<<"["<<(it)->F<<" , "<<(it)->S<<"] ";}puts("");}

#define read2d(a,w,h)   rep(i,h)rep(j,w)cin>>a[i][j]
#define dump2d(a,w,h)   rep(i,h){rep(j,w)cout<<a[i][j]<<" ";puts("");}



li n;
li a[200100];

li dp_minus[200200][16];
li dp_plus[200200][16];

// aを何回4倍するとb以上になるか
inline li calc4(li a, li b) {
    li res = 0;
    while (a < b) {
        a *= 4;
        res++;
    }
    return res;
}

// aを何回4倍するとb*(4^num)以上になるか
inline li calc4_2(li a, li b, li num) {
    li res = 0;
    if (a <= b) {
        res = num;
        num = 0;
    }
    rep(i, num) {
        b *= 4;
    }
    while (a < b) {
        a *= 4;
        res++;
    }
    return res;
}

inline li calc_minus(li x, li num) {
    if (num < 16)return dp_minus[x][num];
    return dp_minus[x][15] + (x + 1) * (num - 15);
}

inline li calc_plus(li x, li num) {
    if (num < 16)return dp_plus[x][num];
    return dp_plus[x][15] + (n - x) * (num - 15);
}

int main() {
    cin >> n;
    rin{cin >> a[i];}

    rep(num, 16) {
        dp_minus[0][num] = num;
        dp_plus[n - 1][num] = num;
    }

    repp(i, 1, n) {
        rep(num, 16) {
            dp_minus[i][num] = num + calc_minus(i - 1, calc4_2(a[i - 1], a[i], num));
        }
    }
    for (li i = n - 2; i >= 0; i--) {
        rep(num, 16) {
            dp_plus[i][num] = num + calc_plus(i + 1, calc4_2(a[i + 1], a[i], num));
        }
    }

    rep(i, n) {
        //p2(dp_minus[i][0], dp_plus[i][0]);
    }

    li res = min(dp_plus[0][0] * 2, dp_minus[n - 1][0] * 2 + n);
    rep(i, n - 1) {
        res = min(res, dp_minus[i][0] * 2 + i + 1 + dp_plus[i + 1][0] * 2);
    }
    cout << res << endl;


    return 0;
}

Measured memory_bytes: 51840