#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// for debug
#define DEBUGs
// -----------
#define NOP do{}while(0)
#ifdef DEBUGw
#include <time.h>
#define TRACE(...) do{printf(__VA_ARGS__);fflush(stdout);}while(0)
#define TRACECR do{putchar_unlocked('\n');fflush(stdout);}while(0)
static clock_t	startclock;
void DEBUGSTART(void){TRACE("--DEBUG MODE --\n");startclock=clock();}
void DEBUGEND(void){startclock=clock()-startclock;TRACE("--finish --\ntime is %.3fms\n",startclock/1000.);}
#else
#define TRACE(...) NOP
#define TRACECR NOP
void DEBUGSTART(void){return;}
void DEBUGEND(void){return;}
#endif
extern int getchar_unlocked(void);
extern int putchar_unlocked(int);
#define PRINCR do{printf("\n");fflush(stdout);}while(0)
#define GETLINE(str) do{char *p;fgets(str,sizeof(str),stdin);p=strchr(str,'\n');if(p)*p='\0';}while(0)
#define REP(a,b) for(int a=0;a<(int)(b);++a)
static char *GETWORD(char* str) {char c;char *cp;cp=&str[0];c=fgetc(stdin);while( c != EOF ){if((c==' ')||( c=='\n')) break;*cp++=c;c=fgetc(stdin);}*cp='\0';return &str[0];}
#define    GETINTS(a,b) {char s[34];int *ap=a;REP(i,b){GETWORD(s);sscanf(s,"%d", ap);ap++;}}
static int GETLINEINT(void) {char s[34];GETLINE(s);return atoi(s);}
static int GETWORDINT(void) {char s[34];GETWORD(s);return atoi(s);}
#define SWAP(type,a,b) do{type _c;_c=a;a=b;b=_c;}while(0)
char sdn[600004];
char shi[300004];
int main(){
	long lN;
	long gt;
	int	num;
	int scc;
	char *cp0,*cpc0,*cpc1;
	int iFirst,iPrev,iNow,iEnd;

	scanf("%ld\n",&lN);
	cp0 = sdn;
	iFirst = GETWORDINT();
	iPrev = iFirst;
	for(long i=1L; i < lN-1; ++i){
		iNow = GETWORDINT();
		if( iPrev < iNow ) {
			*cp0++ = '<';
		} else {
			*cp0++ = '>';
		}
		iPrev = iNow;
		//TRACE("%d,",sdn[i]);
	}
	iEnd = GETWORDINT();
	if( iPrev < iEnd ) {
		*cp0++ = '<';
	} else {
		*cp0++ = '>';
	}
	if( iEnd < iFirst ) {
		*cp0++ = '<';
	} else {
		*cp0++ = '>';
	}

	cpc0 = sdn;
	for(long i=0L; i < lN; ++i){
		*cp0++ = *cpc0++;
	}
	*cp0 = '\0';
	GETLINE(shi);
	TRACE("%s\n",shi);
	cpc0 = strstr( sdn , shi );
	if( cpc0 == NULL ) {
		gt = -1;
	} else {
		gt = (long)(cpc0 - sdn);
	}
	printf("%ld\n", gt );
}