#include <stdio.h>#include <math.h>#include <algorithm>#include <map>#include <string>#include <string.h>#include <queue>#include <set>using namespace std;int p[26];int colors[26][100];pair<int,int> block[200];int dp[200][200];pair<int,int> mid[100][2][20];int mid_sz[100][2];void inline Add_mid0(int idx,int cnt,int cost){for(int i=0;i<mid_sz[idx][0];i++){if(mid[idx][0][i].first<=cnt){if(cost-cnt>=mid[idx][0][i].second-mid[idx][0][i].first) return;}else if(cost-cnt<=mid[idx][0][i].second-mid[idx][0][i].first) {swap(mid[idx][0][i],mid[idx][0][--mid_sz[idx][0]]); i--;}}mid[idx][0][mid_sz[idx][0]++]=make_pair(cnt,cost);}void inline Add_mid1(int idx,int cnt,int cost){for(int i=0;i<mid_sz[idx][1];i++){if(mid[idx][1][i].first<=cnt){if(cost>=mid[idx][1][i].second) return;}else if(mid[idx][1][i].second>=cost) {swap(mid[idx][1][i],mid[idx][1][--mid_sz[idx][1]]); i--;}}mid[idx][1][mid_sz[idx][1]++]=make_pair(cnt,cost);}int main(){int m,n;char c,pre;while(scanf("%d",&m)!=EOF){n=0;memset(p,0,26<<2);while((pre=getchar())&&!isupper(pre));while(1){block[n]=make_pair(pre-'A',p[pre-'A']);dp[n][n]=1;while((c=getchar())&&c==pre) dp[n][n]++;if(dp[n][n]>=m) dp[n][n]=1;else dp[n][n]=m-dp[n][n];colors[pre-'A'][p[pre-'A']++]=n++;if(!isupper(c)) break;pre=c;}for(int i=1;i<n;i++){for(int j=0;j<i;j++) dp[j][i]=dp[j][i-1]+dp[i][i];int ci=block[i].second;mid[ci][0][0]=make_pair(m-dp[i][i],0);mid_sz[ci][0]=1;mid_sz[ci][1]=0;for(int cj=ci-1,j;cj>=0;cj--){j=colors[block[i].first][cj];mid_sz[cj][0]=mid_sz[cj][1]=0;for(int ck=ci,k;ck>cj;ck--){k=colors[block[i].first][ck];for(int i_mid=0;i_mid<mid_sz[ck][0];i_mid++){int cost=dp[j+1][k-1]+mid[ck][0][i_mid].second;if(cost>=dp[j][i]) continue;if(dp[j][j]>mid[ck][0][i_mid].first){Add_mid0(cj,m-dp[j][j]+mid[ck][0][i_mid].first,cost);dp[j][i]=min(dp[j][i],cost+dp[j][j]-mid[ck][0][i_mid].first);}else{Add_mid1(cj,m-dp[j][j],cost);dp[j][i]=cost;}}for(int i_mid=0;i_mid<mid_sz[ck][1];i_mid++){int cost=dp[j+1][k-1]+mid[ck][1][i_mid].second;if(cost>=dp[j][i]) continue;if(dp[j][j]>mid[ck][1][i_mid].first){Add_mid1(cj,m-dp[j][j]+mid[ck][1][i_mid].first,cost);dp[j][i]=cost;}}}for(int k=j-1;k>=0;k--) dp[k][i]=min(dp[k][i],dp[k][j-1]+dp[j][i]);}}printf("%dn",dp[0][n-1]);}}
