#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

#define rd_skip() while(*rp++>=48)
#define rd() ({long _v=0,_c;while(_c=*rp++-48,_c>=0)_v=_v*10+_c;_v;})
#define wt(v) {ulong _z=v;do*--wp=_z%10+48;while(_z/=10);}

typedef unsigned long ulong;

int main(){
	char*mmap();
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	rd_skip();
	long a=-1,z=0,w=0;
	while(*rp){
		long b=rd();
		z+=w=b==a+1?w+1:0;
		a=b;
	}
	char wbuf[64],*wp=wbuf+sizeof wbuf;
	wt(z);
	write(1,wp,wbuf+sizeof wbuf-wp);
	_exit(0);
}