// Author: kyEEcccccc

#include <bits/stdc++.h>

using namespace std;

using LL = long long;
using ULL = unsigned long long;

#define F(i, l, r) for (int i = (l); i <= (r); ++i)
#define FF(i, r, l) for (int i = (r); i >= (l); --i)
#define MAX(a, b) ((a) = max(a, b))
#define MIN(a, b) ((a) = min(a, b))

const int N = 70005;

int f[N][10], g[N][10][10], h[N][10];

void trans_f(int to, int c, int x, int val, int aaa)
{
	if (x == c)
	{
		F(xx, 0, 9)
		{
			if (xx == 4)
			{
				continue;
			}

			MIN(f[to][xx], val + 2);
			MIN(h[to][xx], val + 3);

			F(yy, 0, 9)
			{
				if (yy == 4)
				{
					continue;
				}

				MIN(g[to][xx][yy], val + 3);
			}
		}
	}
	else
	{
		if (!aaa)
		{
			MIN(f[to][x], val);
		}
		MIN(h[to][x], val + 1);
		F(yy, 0, 9)
		{
			if (yy == 4)
			{
				continue;
			}

			MIN(g[to][x][yy], val + 1);
		}
	}
}

void trans_h(int to, int c, int x, int val)
{
	if (c == x)
	{
		F(xx, 0, 9)
		{
			if (xx == 4)
			{
				continue;
			}

			MIN(h[to][xx], val + 3);
		}
	}
	else
	{
		MIN(h[to][x], val + 1);
	}
}

void trans_g(int to, int c, int x, int y, int val)
{
	if (c == x && c == y)
	{
		F(xx, 0, 9)
		{
			if (xx == 4)
			{
				continue;
			}

			MIN(f[to][xx], val + 4);
			MIN(h[to][xx], val + 5);

			F(yy, 0, 9)
			{
				if (yy == 4)
				{
					continue;
				}

				MIN(g[to][xx][yy], val + 5);
			}
		}
	}
	else if (c != x && c != y)
	{
		MIN(g[to][x][y], val + 1);
	}
	else
	{
		MIN(f[to][c ^ x ^ y], val + 2);
		MIN(h[to][c ^ x ^ y], val + 3);

		F(xx, 0, 9)
		{
			if (xx == 4)
			{
				continue;
			}

			if (x == c)
			{
				MIN(g[to][xx][y], val + 3);
			}
			else
			{
				MIN(g[to][x][xx], val + 3);
			}
		}
	}
}

int aa[N];

int main(void)
{
	// freopen(".in", "r", stdin);
	// freopen(".out", "w", stdout);
	ios::sync_with_stdio(0), cin.tie(nullptr);

	int n;
	string s, t;
	cin >> n >> t;
	int is = 0, x = 0;
	F(i, 0, n-1)
	{
		if (t[i] == 'e')
		{
			is = 1;
			x += 2;
		}
		else
		{
			aa[s.size()] = is;
			is = 0;
			s += t[i];
		}
	}
	n = s.size();

	F(i, 0, n-1) F(x, 0, 9) F(y, 0, 9)
	{
		h[i][x] = f[i][x] = g[i][x][y] = INT_MAX / 4;
	}
	F(i, 0, 9)
	{
		if (i != 4)
		{
			f[0][i] = 0;
		}
	}

	F(i, 0, n-2) F(x, 0, 9)
	{
		if (x == 4)
		{
			continue;
		}

		trans_f(i+1, s[i+1] - 'a', x, f[i][x], aa[i]);
		trans_h(i+1, s[i+1] - 'a', x, h[i][x]);

		F(y, 0, 9)
		{
			if (y == 4)
			{
				continue;
			}

			trans_g(i+1, s[i+1] - 'a', x, y, g[i][x][y]);
		}
	}

	int ans = INT_MAX / 4;
	FF(i, n-1, 1)
	{
		ans = min(ans, h[i-1][s[i] - 'a']);
		if (aa[i])
		{
			break;
		}
	}
	ans += x;
	cout << ans + 2 << '\n';

	return 0;
}

交上去就是Judging很久返回编译失败。复制了题解交上去就能测，不知道为啥，我这代码里有什么不能编译或者不能交的东西吗？还是因为宏定义？换过语言，不开O2也试过了，就是不行。把这道题的代码交到别的题目上去立刻评测出RE，为啥交这里连编译都不行？