SAS两阶段交叉设计为什么运行不了,哪里错了

DATA sastjfx4-5;
input period1 $ y1 period2 $ y2@@;
input drug $ y@@;
output;
end;
end;
cards;
A 84.4 B 70.9
A 101.0 B 92.7
A 72.7 B 99.0
A 86.7 B 79.9
A 86.6 B 70.6
A 65.5 B 46.7
A 67.4 B 54.6
A 58.2 B 89.1
A 45.2 B 52.9
A 72.6 B 66.5
A 65.4 B 63.0
A 61.9 B 51.9
B 66.6 A 63.6
B 117.0 A 107.3
B 47.6 A 54.6
B 73.9 A 65.2
B 111.9 A 114.4
B 59.7 A 57.6
B 80.8 A 74.9
B 85.8 A 97.4
B 61.4 A 46.1
B 77.9 A 62.3
B 56.8 A 61.5
B 74.7 A 76.0
;
RUN;
ODS HTML;
proc ttest;
var y1 y2/crossover=(period1 period2);
run;
ods html close;

1. 数据名称
2. 不用end,end
DATA sastjfx4_5;
   input period1 $ y1 period2 $ y2@@;
   cards;
A 84.4 B 70.9
A 101.0 B 92.7
A 72.7 B 99.0
A 86.7 B 79.9
A 86.6 B 70.6
A 65.5 B 46.7
A 67.4 B 54.6
A 58.2 B 89.1
A 45.2 B 52.9
A 72.6 B 66.5
A 65.4 B 63.0
A 61.9  B 51.9
B 66.6 A 63.6
B 117.0 A 107.3
B 47.6 A 54.6
B 73.9 A 65.2
B 111.9 A 114.4
B 59.7 A 57.6
B 80.8 A 74.9
B 85.8 A 97.4
B 61.4 A 46.1
B 77.9 A 62.3
B 56.8 A 61.5
B 74.7  A 76.0
;
RUN;
ODS HTML;
proc ttest;
var y1 y2/crossover=(period1 period2);
run;
ods html close;

搜一下：SAS两阶段交叉设计为什么运行不了,哪里错了