#include <stdio.h>
void abba();
int main()
{
abba();
return 0;
}
void abba()
{
int x = 0;
char c;
while ((scanf("%c", &c
) == 1) && (c
== 'a' || c
== 'b')) { switch (x) {
case 0:
if (c == 'a')
x = 1;
break;
case 1:
if (c == 'b')
x = 2;
break;
case 2:
if (c == 'b')
x = 3;
else
x = 1;
break;
case 3:
if (c = 'b')
x = 0;
else {
}
break;
}
}
}
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