#include <stdio.h>
int main() {
int n,cnt=0;
scanf("%d",&n);
char s[n],S[n];
scanf("%s",s);
for ( int i=0; i<n; i++ )
{
if ( s[i]>='a' && s[i]<='z' )
{
S[cnt] = s[i];
cnt++;
}
}
for ( int i=0; i<n; i++ )
{
if ( s[i]>='0' && s[i]<='9' )
{
S[cnt] = s[i];
cnt++;
}
}
for ( int i=0; i<n; i++ )
{
if ( s[i]>='A' && s[i]<='Z' )
{
S[cnt] = s[i];
cnt++;
}
}
S[cnt] = '\0';//避免输出乱码
printf("%s",S);
return 0;
}

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